Theory of magnetoplasmon resonance lineshape in the silicon inversion layer

The lineshape of the plasma-shifted cyclotron resonance is calculated in the two-dimensional system. The nonlocal effect is taken into account to the lowest order and is shown to be extremely small in the usual experimental conditions. When the peak position is close to the subharmonic structure of the usual cyclotron resonance, a coupling splits the peak into two, explaining recent experiments of Theis et al. The agreement with the experiments is satisfactory.     

Inversion layer resistance in silicon inversion layer solar cells

The inversion layer resistance is very important for metal-insulator-semiconductor inversion layer (MIS/IL) solar cells, and usually it is the main part of the series resistance. It is found that the inversion layer resistance and the junction depth are determined by the operating voltage for an MIS/IL solar cell. On the basis of MIS theory, a general relationship between the operating voltage and the inversion layer resistance (and the junction depth) has been investigated. Practical computations have been done for MIS/IL solar cells with a silicon nitride insulator layer. It is found that the inversion layer resistance has a minimum value for operating voltage near 0.4 V, and the junction depth decreases monotonically with the increase of the operating voltage.     

Variable-range hopping in a silicon inversion layer

The low temperature conductance in the inversion layer of an MNOSFET shows a transition from activated to metallic conduction as the Fermi level is raised. The temperature dependence in the activated region is consistent with two-dimensional variable-range hopping and the minimum metallic conductivity, 4500 Ω^-1m^-1, agrees with a theoretical estimate based on Mott's formula.     

Temperature dependence of the conductivity of a silicon inversion layer at low temperatures

The temperature dependence of the conductivity of a high-mobility silicon MOSFET is reported for temperatures from 0.2 to 23 K and electron densities from 1 to 20 × 10¹¹cm⁻². The results show a strong increase in conductivity with decreasing temperature. However, this rate of increase was observed to rapidly diminish outside of a restricted range of temperature for a given density. The decreasing temperature dependence at the lower temperatures is attributed to the saturation of screening as the effects of broadening become comparable to thermal effects. The diminishing temperature dependence at the higher temperatures puts limits on the applicability of recent calculations for the conductivity.     

Valley splitting in an n-channel (100) inversion layer on p-type silicon

The extended zone effective mass theory is proposed and is applied to the investigation of the valley splitting in an n-channel (100)Si inversion layer. The splitting is due to a tunnelling effect in k-space, and is given approximately as ΔE ≈ 0.15 (N_inv + g^?1N_depl) meV (N_inv and N_depl in units of 10¹² cm^?2$\text{g =}\text{11}\text{32}$). When the strain exists, or when k_x and k_y are both non-zero, the splitting is a little larger than this value. The enhancements of the Zeeman splittings and the valley splittings caused by the many body effects under strong magnetic fields are taken into account. The theory predicts the structure and line shape of the transverse magnetoconductivity oscillations, and the results show a very good agreement with the experiment including the cusps at the peak of the Landau levels in the indices N ? 3.     

Wavevector dependence of the two-dimensional plasmon dispersion relationship in the (100) silicon inversion layer

The two-dimensional plasmon dispersion relationship in the inversion layer on (100) p-silicon is studied as a function of wavevector q. This is facilitated by a simple technique which allows plasmon resonances corresponding to several values of q to be excited in the same sample. Over the experimentally obtained values of q the results are in good agreement with theory.     

Substrate bias effects on the second subband occupation in the electron inversion layer on the (100) silicon surface

Substrate bias effects on the Shubnikov-de Haas oscillations have been studied in the electron inversion layer on the (100) silicon surface. The energy splitting between the ground and the second subbands was found to increase linearly with increasing of the depletion charge. Extrapolation of these results to zero charge density in the depletion layer is in accordance with measurements of the onset of the second subband occupation in the accumulation layer.     

Hot electrons in Si inversion layer

The energy losses per electron to phonons (both acoustic and optical) are calculated for Si(100) inversion layer taking the subband structure of electron energy spectrum fully into account. The electron mobility variations with applied field are studied by energy balance method. We examine two extreme cases: (1) the intervalley transitions connect any pair of subbands in respective valleys with the same transition matrix; (2) the intervalley transitions connect only the lowest subbands in each valley. It turns out that we can choose the magnitude of intervalley transition amplitude such that experimental data lie in between the theoretical results in two cases mentioned above at both lattice temperatures T = 77 and 300 K.     

Dependence on substrate bias of the effective mass and dingle temperature of electrons in the surface inversion layer of silicon

The amplitude of the quantum oscillations in the magnetoconductance of a silicon inversion layer has been studied as a function of gate voltage V_g, for different values of the temperature T, applied magnetic field strength H and substrate bias V_s. By analyzing the amplitude of the oscillations at fixed V_g and V_g as a function of T and H, the dependence of the cyclotron effective mass m¹ and the Dingle temperature T_D on V_g and V_s can be obtained. The dependence of m¹ on V_g for different values of V_s is compared with the prediction of theory.     

Two-dimensional optical micro-scanner on silicon technology

A two-dimensional optical micro-scanner, which main components are two mobile flat and a concave micro-mirrors, is designed such that, all optical components can be fabricated on the same substratum. The optical parameters, which physical dimensions are between 50 and 500 μm, are obtained within the geometrical optics. The optical performance is evaluated by means of the MTF and Rayleigh resolution criteria, given 80% of modulation for a frequency of 8 cycles/mm with a Gaussian source, the resolution limit is 30 μm.     

Comments on the hole mass in silicon inversion layers

Published experimental data for hole masses m_c in silicon inversion layers on (110), (111) and (100) surfaces are critically discussed. New results are presented for the (100) orientation. It is shown that self-consistent calculations of m_c agree with those experimental data, which are compatible with cyclotron resonance results. It is demonstrated that a theoretical treatment by Falicov and Garcia, which predicts too large hole masses, is not tenable.     

Remote polar phonon scattering in silicon inversion layers

A new scattering mechanism for free carriers in inversion layers is proposed. It is shown that polar optical phonons of the insulator couple effectively to the inversion layer electrons in the adjacent semiconductor. For the Si-SiO₂ interface this scattering by remote polar phonons influences substantially the field dependent mobility of the silicon inversion layer carriers.     

First order intervalley scattering in silicon inversion layers

The mobility limited by first order intervalley scattering in a quantized silicon inversion layer is calculated by an iterative solution of the Boltzmann equation incorporating both scattering-out and scattering-in terms. The mobility values are found to be much smaller than those based on a relaxation-time model considering scattering-out only.     

HgCdTe反型层的磁输运性质

利用成本低廉的液相外延技术, 成功制备了具有金属-绝缘体-半导体结构的HgCdTe场效应管器件. 在该器件中, 观察到清晰的Shubnikov-de Hass振荡和量子霍尔平台, 证明样品具有较高的质量. 测量零场附近的磁阻曲线, 在HgCdTe-基器件中观察到反弱局域效应, 表明样品中存在较强的自旋-轨道耦合作用. 利用Iordanskii-Lyanda-Pikus理论, 很好地拟合了反弱局域曲线. 由拟合得到的自旋分裂能随电子浓度的增大而增大, 最大达到9.06 meV. 根据自旋分裂能得到的自旋-轨道耦合系数同样随电子浓度的增大而增大, 与沟道较宽的量子阱中所得到的结果相反.     

Electron-electron interactions in the surface inversion layer of a semiconductor

The effective unscreened interaction between a pair of electrons in the inversion layer of an MIS structure is estimated by using classical electrostatics together with a knowledge of the quantum mechanical wave function of the inversion layer electrons. The change in the effective mass $\text{m}{}^1$ and effective g-value g¹ are evaluated in the random phase approximation.